Mri biopsy device

ABSTRACT

A localization mechanism, or fixture, is used in conjunction with a breast coil for breast compression and for guiding a core biopsy instrument during prone biopsy procedures in both open and closed Magnetic Resonance Imaging (MRI) machines. The localization fixture includes a three-dimensional Cartesian positionable guide for supporting and orienting an MRI-compatible biopsy instrument, and in particular a sleeve, to a biopsy site of suspicious tissues or lesions. A depth stop enhances accurate insertion, and prevents over-insertion or inadvertent retraction of the sleeve. The sleeve receives a probe of the MRI-compatible biopsy instrument and may contain various features to enhance its imagability, to enhance vacuum and pressure assist therethrough, and marker deployment etc.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. provisional patentapplication entitled “MRI BIOPSY DEVICE” to Hughes et al., Ser. No.60/573,510, filed on 21 May 2004, the disclosure of which is herebyincorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates, in general, to a method of imagingassisted tissue sampling and, more particularly, to an improved methodfor positioning a biopsy probe with respect to a magnetic resonanceimaging (MRI) breast coil for acquiring subcutaneous biopsies and forremoving lesions.

BACKGROUND OF THE INVENTION

Recently, core biopsy devices have been combined with imaging technologyto better target a lesion in breast tissues. One such commerciallyavailable product is marketed under the trademark name MAMMOTOME™, byEthicon Endo-Surgery, Inc. An embodiment of such a device is describedin U.S. Pat. No. 5,526,822 issued to Burbank, et al., on Jun. 18, 1996,and is hereby incorporated herein by reference. Its handle receivesmechanical and electrical power as well as vacuum assist from a remotelypositioned control module that is spaced away from the high magneticfield of a Magnetic Resonance Imaging (MRI) machine.

As seen from that reference, the instrument is a type of image-guided,percutaneous coring, breast biopsy instrument. It is vacuum-assisted,and some of the steps for retrieving the tissue samples have beenautomated. The physician uses this device to capture “actively” (usingthe vacuum) the tissue prior to severing it from the body. This allowsthe sampling of tissues of varying hardness. In addition, a side openingaperture is used, avoiding having to thrust into a lesion, which maytend to push the mass away, causing a track metastasis, or causing ahematoma that, with residual contrast agent circulating therein, maymimic enhancement in a suspicious lesion. The side aperture may berotated about a longitudinal axis of the probe, thereby allowingmultiple tissue samples without having to otherwise reposition theprobe. These features allow for substantial sampling of large lesionsand complete removal of small ones.

In MRI, the presence of both the magnetic and RF fields used in theimaging process place several constraints on each instrument to bepositioned or manipulated near or in the imaging region of the MRIsystem. The MRI system imposes a strong constant magnetic field (e.g, 1Tesla) to align electrons of the atoms of the body. Then a magneticgradient is applied to disturb these aligned electrons. As the electronsreturn to alignment, a weak RF signal is emitted that must be detectedand interpreted. Compatibility with such an environment requires thatthe instrument must be essentially non-ferromagnetic, so that it is notattracted by the magnetic field and thus posing, which would pose asafety problem. This consideration applies to any object that is usednear (or that is inserted into or implanted within) the patient beingimaged, because the magnetic field subjects such an object or implants,if ferro-magnetic, to undesirable forces and torques. In addition, anelectrical instrument should be tolerant of the static and pulsedmagnetic and RF fields in order to be operable in the presence of thesefields. Further, an implant or instrument should not be unduly subjectto induced heating due to eddy current from the applied RF field.Finally, the instrument should not create excessive imaging artifactsthat obscure or distort the image of the target.

To address these constraints, MRI compatible biopsy instruments aregenerally assembled from non-ferrous materials; however, other materialsthat are MRI imagable. are sometimes used. In some instances,imagability relies upon the lack of an MRI RF return image to constrastwith the image returned by adjacent tissue. Also, ferromagneticparticles or liquid lumens for holding aqueous paramagnetic ions aresometimes incorporated.

While these generally-known MRI biopsy devices provide MRI compatibilityand a degree of imagability, further improvements would be desirable.More particularly, a significant need exists for an MRI compatiblebiopsy device that may assist in penetrating tissue, that enhanceslocating a sampling aperture in an MRI compatible penetrating portion,even in an MRI scan slice that obliquely passes through the probe, andthat facilitates other therapeutic steps through the penetratingportion.

BRIEF SUMMARY OF THE INVENTION

The invention overcomes the above-noted and other deficiencies of theprior art by providing a sleeve and obturator combination thatfacilitate minimally invasive procedures guided by diagnostic imaging byproviding improvements in confirmation of sleeve placement and handsfree continued access through the sleeve for a myriad of diagnostic andtherapeutic procedures.

In one aspect of the invention, an apparatus performs a minimallyinvasive medical procedure into human breast tissue through a cannulaformed of a magnetic resonance imaging (MRI) compatible material andincluding an open proximal end and a more distal opening. An obturatorhas a hollow shaft also formed of MRI compatible material and sized forinsertion into the cannula. The obturator has a structure proximate tothe more distal opening of the cannula when thus inserted into thecannula that controls prolapsing of tissue therein. Confirmation ofplacement of the cannula is accentuated by an MRI imagable portion ofthe obturator proximate to the more distal opening of the cannula. Alumen formed in the obturator communicates between a proximal portionexternal to the human breast tissue and the more distal opening of thecannula. Thereby, the obturator provides flexibility in performing stepssuch as transferal of pneumatic pressure for insufflation and markerdeployment, removal of excess fluid, insertion of pharmacological oranesthetic substances or other procedures. In situations in which *MRIimaging allows real-time confirmation of placement, the sleeve andobturator provides a means of accurately placing the cannula whilemitigating tissue trauma as well as enabling treatments through thecombination.

In another aspect of the invention, an apparatus is included for usewith a biopsy device in a medical procedure wherein a patient has a bodyportion localized within a localization fixture having a guidanceportion. The apparatus includes a sleeve having a hub supported andguided by the guidance portion of the localization fixture. The sleevehas a cannula that is inserted into the tissue with the assistance of anobturator, one of the two having a piercing tip. The cannula is sized toreceive the elongate probe from a proximal direction through the sleevehub. Thereby, clinical flexibility is achieved by being able to performa number of therapeutic and diagnostic procedures hands free through thesleeve even within the close confines of certain diagnostic imagingmodalities such as magnetic resonance imaging.

The present invention shall be made apparent from the accompanyingdrawings and the description thereof.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the invention,and, together with the general description of the invention given above,and the detailed description of the embodiments given below, serve toexplain the principles of the present invention.

FIG. 1 is a perspective disassembled view of a Magnetic ResonanceImaging (MRI) compatible biopsy system incorporating a guided sleeve andobturator, advantageously MRI compatible and imagable, and providingtherapeutic features;

FIG. 2 is a disassembled perspective view of a guidance portion of alocalization fixture and a disassembled MRI biopsy device of the MRIcompatible biopsy system of FIG. 1;

FIG. 3 is a perspective view of the MRI biopsy device of FIG. 2, mountedon the guidance portion of the localization fixture;

FIG. 4 is a perspective disassembled view of an alternative guidanceportion, including a cradle supporting a sleeve having open distal endand side aperture, an imaging obturator with a piercing tip, and a fluidcommunicating stylet that is also used to place a marker for the MRIcompatible biopsy system of FIG. 1;

FIG. 5 is a perspective disassembled view of a further alternativeguidance assembly supporting a sleeve with an imaging/marking obturatorhaving a fluid lumen and piercing tip;

FIG. 6 is a right side diagrammatic view in elevation taken inlongitudinal cross section of the sleeve with an open distal end andlateral aperture and introducer, imaging obturator of FIG. 5 with theobturator having a dug-out marker recess;

FIG. 7 is a right side diagrammatic view in elevation, taken inlongitudinal cross section of a sleeve with a side aperture and piercingtip used with an introducer, imaging obturator having a dug-out markerrecess for the MRI compatible biopsy system of FIG. 1;

FIG. 8 is a right side diagrammatic view in elevation taken inlongitudinal cross section of a sleeve with a lateral aperture and opendistal end used with an introducer, imaging obturator having anon-cylindrical cross section and piercing tip for the MRI compatiblebiopsy system of FIG. 1;

FIG. 9 is a right side diagrammatic view in elevation taken inlongitudinal cross section of the sleeve of FIG. 7 with an introducer,imaging obturator having a non-cylindrical cross section for the MRIcompatible biopsy system of FIG. 1;

FIG. 10 is a right side diagrammatic view in elevation taken inlongitudinal cross section of a sleeve with an asymmetric piercing tipand lateral aperture with an imaging obturator;

FIG. 11 is a front view in transverse cross section of a proximalportion of the imaging obturator of FIG. 10 taken along lines 11-11 toexpose an X-shaped cross section thereof;

FIG. 12 is a back view in transverse cross section of a distal portionof the imaging obturator of FIG. 10 taken along lines 12-12 depictingthe X-shaped cross section shaping the prolapse of tissue into the sideaperture of the sleeve;

FIG. 13 is a front view in transverse cross section of a proximalportion of an alternate imaging obturator of FIG. 10, taken along lines11-11 to expose a ridged half-cylinder cross section thereof;

FIG. 14 is a back view in transverse cross section of a distal portionof an alternate obturator of FIG. 10, taken along lines 12-12 depictingthe ridged half-cylinder section, shaping the prolapse of tissue intothe side aperture of the sleeve;

FIG. 15 is a right side view in elevation, taken in longitudinal crosssection of an alternate imaging obturator, having an asymmetric piercingtip and having a dug-out recess capturing an MRI visible insert;

FIG. 16 is a right side view in elevation taken in longitudinal crosssection of an alternate imaging obturator, having an asymmetric piercingtip and having an internal, proximally communicating cavity holding adistally positioned MRI visible insert;

FIG. 17 is a right side view in elevation taken in longitudinal crosssection of an alternate imaging obturator, having an internal,proximally communicating cavity configured to draw body fluid into adug-out recess;

FIG. 18 is a right side view in elevation taken in longitudinal crosssection of the alternate imagingmarker obturator of FIG. 17 afterdrawing tissue into the side aperture of the sleeve to present an MRIvisible contour;

FIG. 19 is a right side view in elevation, taken in longitudinal crosssection of the alternate imagingmarker obturator of FIG. 17 with an MRIvisible material contained within a sheath-covered lateral notch;

FIG. 20 is a right side view in elevation taken in longitudinal crosssection of an assembled imagingmarker obturator, including a solidstylet having a lateral notch and encompassed by a penetrating sheathwith a molded, asymmetric piercing tip;

FIG. 21 is a right side view in elevation, taken in longitudinal crosssection of an obturator, having an open distal end and a lateralaperture with vacuum assisted air evacuation to allow a marker lumen tofill with bodily fluids to present an MRI visible material;

FIG. 22 is a right side view in elevation, taken in longitudinal crosssection of an obturator having a piercing distal end and a lateralaperture with vacuum assisted air evacuation to allow a marker lumen tofill with bodily fluids to present an MRI visible material;

FIG. 23 is a right side view in elevation, taken in longitudinal crosssection of an obturator having a closed, blunt distal end and a markerlumen containing an MRI visible material (e.g., gadolinium solution,aqueous solution) having an MRI dark plug (e.g., collagen, nonferrousmetal, plastic) positioned and containing fluid passages to correspondto a side aperture of a sleeve;

FIG. 24 is a right side view in elevation, taken in longitudinal crosssection of an obturator having a piercing distal end and a marker lumencontaining an MRI visible material (e.g., gadolinium solution, aqueoussolution) having an MRI dark plug (e.g., collagen, nonferrous metal,plastic) positioned and containing fluid leak passages to correspond toa side aperture of a sleeve;

FIG. 25 is a right side view in elevation, taken in longitudinal crosssection of an obturator having a piercing distal end and a marker lumencontaining an MRI visible material (e.g., gadolinium solution, aqueoussolution) having an MRI dark plug (e.g., collagen, nonferrous metal,plastic) positioned and containing fluid passages to communicate with anobturator side aperture;

FIG. 26 is a side view in elevation of a sleeve having a notch and anopen distal end with an imaging obturator shown in phantom for the MRIcompatible biopsy system of FIG. 1.

FIG. 27 is a cross section view, taken along lines 27-27 perpendicularto a longitudinal axis of the sleeve of FIG. 26;

FIG. 28 is a side view in elevation of the obturator of FIG. 26 with anupper portion, which slidingly engages longitudinally a bottom portionalong a dovetail joint, proximally drawn for exposing a notch in thesleeve;

FIG. 29 is a cross section view, taken along lines 29-29 perpendicularto a longitudinal axis of the obturator of FIG. 28 showing anoval-shaped sleeve lumen;

FIG. 30 is a side view in elevation of a sleeve with an integral sharpattached to a shaft having a circular cutter lumen and an underlyingvacuum lumen;

FIG. 31 is a cross section view taken along line 31-31 perpendicular toa longitudinal axis of the sleeve of FIG. 30 showing a circular cutterlumen and underlying vacuum lumen;

FIG. 32 is a side view in elevation of the sleeve of FIG. 31, cut awayto expose a rotatable obturator that selectively closes a notch in thesleeve;

FIG. 33 is a cross section view taken along line 33-33 perpendicular toa longitudinal axis of the sleeve of FIG. 32;

FIG. 34 is a depiction of an MRI display with the selected imaging slicepassing substantially along the longitudinal length of a coaxial sleeveand obturator of FIG. 28 with the obturator in its closed position toblock the notch of the sleeve;

FIG. 35 is a depiction of an MRI display with the selected imaging slicepassing perpendicularly through the longitudinal length of the coaxialsleeve and obturator of FIG. 34, taken along lines 35-35;

FIG. 36 is a depiction of an MRI display with the selected imaging slicepassing substantially along the longitudinal length of a coaxial sleeveand obturator of FIG. 28 with the obturator in its open position to openthe notch of the sleeve;

FIG. 37 is a depiction of an MRI display with the selected imaging slicepassing perpendicularly through the longitudinal length of the coaxialsleeve and obturator of FIG. 36, taken along lines 37-37;

FIG. 38 is a perspective view of proximal ends of an obturator andsleeve, partially cut away to show a bayonet-style attachment for theMRI compatible biopsy system of FIG. 1.

FIG. 39 is a perspective view of proximal ends of an obturator andsleeve, partially cut away to show a threaded connection for the MRIcompatible biopsy system of FIG. 1.

FIG. 40 is a perspective view of proximal ends of an obturator andsleeve, partially cut away to show a button release for the MRIcompatible biopsy system of FIG. 1;

FIG. 41 is a perspective view of a sleeve partially cut away to expose asingle port in its base, distal to a septum or full diameter seal;

FIG. 42 is a cross section view along the longitudinal axis of thesleeve of FIG. 41;

FIG. 43 is a perspective view of a sleeve, partially cut away to exposea single port in its base, distal to an O-ring dynamic seal;

FIG. 44 is a cross section view along the longitudinal axis of thesleeve of FIG. 43;

FIG. 45 is a perspective view of a sleeve, partially cut away to exposetwo ports longitudinally spaced along its base with an O-ring dynamicseal therethere between and another O-ring dynamic seal, distal to both;

FIG. 46 is a cross section view along the longitudinal axis of thesleeve of FIG. 45;

FIG. 47 is a right side view in elevation, taken in longitudinal crosssection of an obturator having a sharp tip shielded within a sheath;

FIG. 48 is a right side view in elevation, taken in longitudinal crosssection of the obturator of FIG. 47 having a sharp tip shielded within asheath;

FIG. 49 is a right side view in elevation taken in longitudinal crosssection of an obturator, having a sharp tip selectively shielded by asplit sheath that is stored within the obturator;

FIG. 49A is a front view of the obturator of FIG. 49, taken in crosssection along lines 49A-49A;

FIG. 50 is a right side view in elevation, taken in longitudinal crosssection of a sleeve incorporating a flap distal closure that isselectively actuated on a sleeve to shield a sharp tip;

FIG. 51 is a front view in elevation of the distal flap closure andsharp tip of the obturator and sleeve of FIG. 50;

FIG. 52 is a front view in elevation of an alternate distal flap closurewith three flaps for the sleeve of FIG. 51;

FIG. 53 is a right side view in elevation, taken in longitudinal crosssection of a distal portion of the sleeve of FIG. 50, with closed distalflap closure and an obturator with a protected sharp tip shown inphantom;

FIG. 54 is a front view in elevation, taken in cross section along lines54-54 of a proximal portion of the sleeve of FIG. 50;

FIG. 55 is a right side view in elevation, taken in longitudinal crosssection of a distal portion of an obturator having a lateral notchaccentuated by an MRI visible marker and communicating with a markerdeployment lumen;

FIG. 56 is a right side view in elevation, taken in longitudinal crosssection of a distal portion of an obturator having a lateral notchaccentuated by flanking marker bands and communicating with anunderlying vacuum lumen;

FIG. 57 is a right side view in elevation, taken in longitudinal crosssection of an obturator with a side notch with a deployment ramp andmarker/tool lumen;

FIG. 58 is a right side view in elevation, taken in longitudinal crosssection of a core needle having an annular ring MRI visible marker aboutan open distal end that communicates with a longitudinal marker/toollumen;

FIG. 59 is a right side view in elevation, taken in longitudinal crosssection of a sleeve with a distal opening and a side aperture thatselectively communicates with a longitudinal lumen with an adapterpositioned in a first position;

FIG. 60 is a right side view in elevation, taken in longitudinal crosssection of the sleeve of FIG. 59 with the adapter in a second position;

FIG. 61 is a right side view in elevation of a curl-biased tool rotatedto deflect tip up;

FIG. 62 is a right side view in elevation taken in longitudinal crosssection of a sleeve with the curl-biased tool tip extending through aside aperture of the sleeve;

FIG. 63 is a right side view in elevation of the curl-biased tool ofFIG. 61 rotated a half rotation to deflect tip down;

FIG. 64 is a right side view in elevation taken in longitudinal crosssection of the sleeve of FIG. 6 with the curl-biased tool tip extendingthrough a distal opening of the sleeve;

FIG. 65 is a right side view in elevation taken in longitudinal crosssection of a sleeve having a push slide distally extended to direct atool out a side aperture;

FIG. 66 is a right side view in elevation taken in longitudinal crosssection of the sleeve of FIG. 65 having the push slide retracted toallow the tool to extend out of a distal opening;

FIG. 67 is a right side view in elevation taken in longitudinal crosssection of the sleeve of FIG. 62 with a plug inserted into the distalend to divert a tool out the side aperture.

FIG. 68 is a right side view in elevation taken in longitudinal crosssection of a sleeve with an open distal end pneumatically sealed to a anobturator with an imagable side notch with an underlying MRI brightmarker;

FIG. 69 is a right side view in elevation taken in longitudinal crosssection of the sleeve of FIG. 68 pneumatically sealed to a marker styletwith a side aperture accentuated by an underlying MRI bright marker andcommunicating with a marker/tool lumen proximally sealable by leurfitting a coupled cap/handle;

FIG. 70 is a right side view in elevation taken in longitudinal crosssection through the sleeve of FIG. 68 with a core needle styletpneumatically sealed therein;

FIG. 71 is a diagrammatic view of a process to produce polymide for anMRI biopsy device;

FIGS. 72A-7D are cross sectional views of a round, oval,square/rectangular, and complex-shaped sleeve;

FIG. 73A is a front view of a perform sleeve placed within a compressionfixture;

FIG. 73B is a front view of the sleeve of FIG. 73A after lateralcompression to form an oval cross sectional shape;

FIG. 73C is a front view of the oval sleeve of FIG. 73B after heating toform a cohesive permanent shape;

FIG. 74A is a front view of a perform round sleeve positioned in aforming fixture of a waisted oval mandrel inserted through the sleeveand the sleeve placed between compression plates having opposingpinching portions;

FIG. 74B is a front view of the perform round sleeve after compressionand heating of the forming fixture of the compression plates against themandrel with the perform sleeve trapped therebetween to acquire awaisted oval shape;

FIG. 74C is a front view of the waisted oval sleeve after release fromthe forming fixture of FIG. 74B;

FIG. 74D is a front view of a forming fixture with compression platesand mandrel shaped to constrain the perform sleeve for compression andheating in a full circumference to form a waisted oval shape;

FIG. 74E is a front view of the waisted oval shaped sleeve after releasefrom the forming fixture of FIG. 74D;

FIG. 75 is a perspective view of a sleeve with laser formed proximalmounting holes for overmolding and side aperture;

FIG. 76A is a right side view in elevation through a longitudinal crosssection of a proximal portion of a sleeve having laser formed throughholes over molded with a sleeve hub;

FIG. 76B is a right side view in elevation through a longitudinal crosssection of a proximal portion of a sleeve having a laser formed relievedarea over molded to form a sleeve hub;

FIG. 77 is a top diagrammatic view of a dual point flat blade attachedin a slot in a conic distal piercing tip of an obturator or sleeve;

FIG. 78A is a top diagrammatic view of a primary/secondary conicpiercing tip of an obturator or sleeve;

FIG. 78B is a front view in elevation of the primary/secondary conicpiercing tip of FIG. 78A;

FIG. 79 is a geometric diagram of insertion torques for positive anglesfor the piercing tip of FIGS. 78A-78B;

FIG. 80 is a geometric diagram of insertion torques for negative anglesfor the piercing tip of FIGS. 78A-78B;

FIG. 81A is a perspective view of an alternate flat, triangular cuttingmember for a piercing portion of a sleeve or obturator;

FIG. 81B is a top view of the alternate flat, triangular cutting memberof FIG. 81A;

FIG. 82 is a left side view in elevation of an obturator with flatbladed piercing tip, lumen communicating between a lateral notch andfluid fitting on a proximal end with external engaging features for anobturator hub;

FIG. 83 is a front view in elevation of the obturator of FIG. 82;

FIG. 84 is a left side view in elevation of a longitudinal cross sectionof the obturator of FIG. 83 taken along lines 84-84;

FIG. 85 is a front view in elevation of the obturator of FIG. 82 takenin cross section along lines 85-85 distal to a hub engaging portion;

FIG. 86 is a front view in elevation of the obturator of FIG. 82 takenin cross section along lines 86-86 across the hub engaging portion;

FIG. 87 is a right sideview in elevation, taken in longitudinal crosssection of the short fiducial instrument having a valve body attached toa hollow snout with a proximal fill spout sealed by a septum andproximally extending from the valve body and with the distal end of anelongate cavity in the hollow snout partially sealed by a porous plug;and

FIG. 88 is a right side view in elevation, taken in longitudinal crosssection of the long fiducial instrument having an integral valve bodyportion formed with a hollow snout portion with a proximal pipe fittingproximally extending from the valve body portion and with the distal endof an elongate cavity in the hollow snout portion partially sealed by avent hole.

DETAILED DESCRIPTION OF THE INVENTION

Turning to the Drawings, wherein like numerals denote like componentsthroughout the several views, in FIG. 1, a Magnetic Resonance Imaging(MRI) compatible biopsy system 10 includes a guide that guides a sleeveand introducer obturator that are separate from the biopsy device itselfand advantageously incorporate an improved piercing portion, MRI imagingmarker, and fluid handling capabilities. Mounting provisions allow forprecise penetration along a desired trajectory without overshooting.

The MRI compatible biopsy system 10 includes a control module 12 thattypically is placed outside of a shielded room containing an MRI machine(not shown) or at least spaced away to mitigate detrimental interactionwith its strong magnetic field and/or sensitive radio frequency (RF)signal detection antennas. The control module 12 controls and powers anMRI biopsy device 14 that is compatible for use in close proximity tothe MRI machine. An example of an MRI biopsy device 14 is theafore-mentioned MAMMOTOME™ instrument. The MRI biopsy device 14 isaccurately positioned by a localization fixture 16 that is attached to abreast coil 18, which in turn supports a patient (not shown). Examplesof commercially available breast coils 18 include the BIOPSY BREAST COILMODEL BBC by MRI DEVICES CORPORATION of Waukesha Wis. A guidanceassembly 20, and, in particular, a sleeve 22, advantageously attaches tothe localization fixture 16 to increase imaging and therapeuticflexibility and accuracy in conjunction with selective use of the MRIbiopsy device 14 during particular parts of the procedure. The guidanceassembly 20 may include one or more obturators 24 with one depicted thatseals the sleeve 22 during insertion and during subsequent portions ofthe procedure in which the MRI biopsy device 14 is not inserted therein.A depth stop 26 is provided for use with the localization fixture 16 toadvantageously prevent over-insertion of the sleeve 22, inadvertentretraction of the sleeve 22 and/or to enhance accurate placement of thesleeve 22 to a desired location along the Z-Axis.

For convenience, herein a convention is used for locating a suspiciouslesion by Cartesian coordinates within breast tissue referenced to thelocalization fixture 16 and to thereafter position an instrument (e.g.,sleeve 22 ) to this location without necessarily continuously imagingthe region. As will be described in greater detail below, a perforatedbarrier that is compressed along an outside side of the breast, withrespect to a medial plane of the chest of the patient defines an X-Yplane, with the X-axis being vertical (sagittal) with respect to astanding patient and which corresponds to a left to right axis as viewedby a clinician facing the externally exposed portion of the localizationfixture 16. A fiduciary marker (not shown)), attached to or positionedrelative to the localization fixture 16 proximate to the patient's skin,defines the origin of this plane. Perpendicular to this X-Y plane andextending toward the medial side of the breast is the Z-axis, whichtypically corresponds to the orientation and depth of insertion of theMRI biopsy device 14, although it should be appreciated that variationsmay allow insertion at an angle to this Z-axis. Thus, for clarity, theterm Z-axis may be used interchangeably with “axis of penetration”,although the latter may or may not be orthogonal to the spatialcoordinates used to locate an insertion point on the patient.

Separating the tracking rail, that supports a mount/depth stop from abiopsy rail that supports the weight of the biopsy device,advantageously reduces interference between the various components,allowing a sequence of operation wherein certain components may beselectively installed and removed without interfering with othercomponents.

In use, the MRI compatible biopsy system 10 is prepared for use byplacing a cable management spool 30 upon a cable management attachmentsaddle 32 that projects from a side of the control module 12. Wound uponthe cable management spool 30 is a paired electrical cable 34 andmechanical cable 36 for communicating control signals and cutterrotation/advancement motions respectively. In particular, electrical andmechanical cables 34, 36 each have one end connected to respectiveelectrical and mechanical ports 40, 42 in the control module 12 andanother end connected to a holster 44 that receives the MRI biopsydevice 14. An MRI docking cup 46, which may hold the holster 44 when notin use, is hooked to the control module 12 by a docking station mountingbracket 48.

An interface lock box 50, mounted to a wall, provides a tether 52 to alockout port 54 on the control module 12. The tether 52 isadvantageously, uniquely terminated and of short length to precludeinadvertent positioning of the control module 12 too close to the MRImachine. An in-line enclosure 56 may advantageously register the tether52, electrical cable 34 and mechanical cable 36 to their respectiveports 54, 40, 42 on the control module 12. A remote keypad 58 may bedistally connected to the electrical cable 34 to enhance cliniciancontrol of the MRI biopsy device 14, especially when controls on the MRIbiopsy device 14 itself are not readily accessible after insertion intothe localization fixture 16.

Vacuum assist is provided by a first vacuum line 60 that connectsbetween the control module 12 and an outlet port 62 of a vacuum canister64 that catches liquid and solid debris. A tubing kit 66 completes thepneumatic communication between the control module 12 and the MRI biopsydevice 14. In particular, a second vacuum line 68 is connected to aninlet port 70 of the vacuum canister 64. The second vacuum line 68divides into two vacuum lines 72, 74 that are attached to the MRI biopsydevice 14. With the MRI biopsy device 14 installed in the holster 44,the control module 12 performs a functional check. Saline is manuallyinjected into biopsy device 14 to serve as a lubricant and to assist inachieving a vacuum seal. The control module 12 actuates a cuttermechanism (not shown) in the MRI biopsy device 14, monitoring fulltravel.

The portion of the MRI compatible biopsy system 10 used near the MRImachine is also assembled. The generally known breast coil 18 is placedupon a gantry of the MRI machine, along with other body support pads(not shown). The localization fixture 16, which is attached within arecess on either lateral side of the breast coil 18 to access apatient's breast that is pendulously exposed therein, includes ahorizontal medial plate 80, a reusable base assembly 82, a lateralassembly 84, and a positioning pedestal 86. The localization fixture 16is also assembled with a disposable medial fence 90 and a lateral window(or perforated plate) 92.

The base assembly 82 is placed within a selected lateral recess of thebreast coil 18. The medial fence 90 attaches to a medial edge of themedial plate 80, aligned vertically approximately along a longitudinalaxis of the breast coil 18 under an inner edge of a selected breastaperture 94 that receives a patient's breast. With the patient thuspositioned and the outer area of the breast sterilized, the lateralwindow 92 is downwardly slid into a three-sided frame guide 96 of thelateral assembly 84, which in turn is placed upon the medical plate 80.The base assembly 82 and lateral assembly 84 are moved with respect toone another along the Z-axis to compress the patient's breast betweenthe medial fence 90 and the lateral window 92. A mechanism formedbetween the lateral assembly 84, base assembly 82, and medial plate 80maintains this compression.

Contrast agent may be injected into the patient to enhance the imaging.The gantry is advanced into the MRI machine bore to image thelocalization fixture 16 and breast tissue. The fiduciary marker on thelateral window 92 is located and designated as the origin of the X-Y-Zcoordinates. Then a suspicious lesion is located within the image and apoint thereon selected to determine its location relative to the origin.It should be appreciated that orienting the X-Y-Z axis of an initialscan may be facilitated by having the lateral window 92 formed of animagable material, thus presenting an X-Y plane in addition to theorigin point of the fiduciary marker. With the target locationdetermined, the gantry is withdrawn from the MRI machine bore.

The positioning pedestal 86 is slidably engaged along the X-axis of thelateral assembly 84 and defines a vertical guide for positioning asingle targeting rail (“track”) 98 at a selected Y-axis coordinate. Thetrack 98 in turn provides a depth guide along the Z-axis for positioningthe depth stop 26 and the holster 44 at a desired Z-axis coordinate. Thedepth stop 26 is latched onto the track 98. Thereafter, a markinginstrument (not shown) may be inserted through the depth stop 26 to markthe insertion point on the breast. Thereafter, the depth stop 26 ismoved out of the way. Anesthesia is injected superficially, followed bya scoring cut at the marked location and a subsequent injection ofanesthesia more deeply into the scored cut. The depth stop 26 is thenrepositioned on the track 98 to the desired Z-axis coordinate reference.

The obturator 24 is inserted into the sleeve 22 and may be positioned toclose any apertures of the sleeve 22 (side and/or distal end) to presenta closed surface to the breast tissue. The obturator may also be shapedor formed to enhance the visibility of the aperture location. One or theother of the obturator 24 and sleeve 22 presents a sharp tip (not shown)to penetrate breast tissue. For instance, if using a sleeve 22 having anopen end, an obturator may provide a sharp tip.

The obturator 24 is inserted into the sleeve 22 and the combination isguided by the track 98 to a proper orientation until an accurate depthis reached as set by the depth stop 26. Once fully inserted, the depthstop 26 prevents over-insertion. The sleeve 22 advantageously latches tothe track 98 and/or the depth stop 26 to prevent inadvertent retraction,such as when the obturator 24 is withdrawn, and pressure is receivedfrom the breast tissue or later when a probe 100 of the MRI biopsydevice 14 is withdrawn from the sleeve 22.

The gantry is moved into the MRI machine bore and the patient is imagedagain to confirm placement of the sleeve 22 with respect to thesuspicious lesion. Advantageously, imagable materials of the sleeve 22and/or obturator 24, perhaps comprising or including marker material,enhance the ability to confirm the location of the sleeve 22 and itssleeve side aperture 102 as positioned for subsequent biopsy samples.

The patient is removed from the MRI machine by retracting the gantry andthe holstered MRI biopsy device 14 is brought to the localizationfixture 16. A protective cap (not shown) is removed from the probe 100of the MRI biopsy device 14 and the obturator 24 is removed from thesleeve 22. Mounting of the holster 44 to the track 98 is shown in FIGS.2 and 3, wherein the holster 44 and MRI biopsy device 14 combinationslide onto the track 98 that has been positioned at a certain locationwith respect to the pedestal 86 and lateral assembly 84. Features of thesleeve 22 and probe 100 may advantageously visually and mechanicallyorient a probe side aperture 104 of the probe 100 with the sleeve sideaperture 102, as well as forming a gas seal. Advantageously, the holster44 and/or the probe 100 may latch onto the track 98 or sleeve 22 toconfirm full insertion and prevent over-insertion and inadvertentretraction. The holster 44 allows an MRI biopsy device 14, intended forhandheld use, to have sufficient support in its attachment to thelocalization fixture 16 to accurately maintain its position and to avoidor minimize loads carried by the probe 100.

Thereafter, the MRI compatible biopsy system 10 may take tissue samplesby activating a cutter mechanism in conjunction with vacuum assist,withdrawing the cutter and withdrawing a tissue sample, the latterperhaps also with vacuum assist. The probe 100/sleeve 22 combination iscapable of manual, or perhaps automatic, rotation to a desired anglewith respect to-their longitudinal axis for additional samples oradditional samples may be taken at the current orientation by furtherresorting to vacuum assist. The cutter is then advanced to close theprobe side aperture 104 and the holster 44 is withdrawn from thelocalization fixture 16, thereby removing the probe 100 from the sleeve22.

Additional steps or combinations of steps may be performed at thispoint, such as using the probe 100, a specialized obturator 24 (e.g.,stylet), or merely the sleeve 22 to guide various agents to the surgicalsite of the biopsy. Examples include draining fluids, insertinganesthetic agents, inserting hemostatic agents, insulating withpneumatic pressure and inserting a marker for subsequently locating thesite of the biopsy, or other diagnostic or therapeutic procedures.

The patient is then typically drawn back into the MRI machine bore forreimaging to confirm removal of at least a portion of the suspiciouslesion and possibly placement of a marker. During this reimaging, thesleeve 22 is sealed with the obturator or stylet 24. Thereafter, thelocalization fixture 16 is removed, the patient is bandaged and removedfrom the gantry, and the disposable portions of the MRI compatiblebiopsy system 10 are disposed of as medical waste.

With particular reference to FIGS. 2-3, the single targeting rail 98facilitates sequential mounting of separate components. First, the depthstop 26, then the sleeve 22 (as in FIG. 1), and then the biopsy tool 14is slid onto the single targeting rail 98. Alternatively as depicted inFIGS. 2-3, the single targeting rail 98 may receive the depth stop 26and then an MRI biopsy device 14 is used without a separate sleeve 22.The maximum depth of penetration into the patient's breast is preset bythe location of the depth stop 26 on the single targeting rail 98. Anengagement mechanism between the holster 44 and the single targetingrail 98 (not shown) and/or an engagement mechanism formed by a catch,depicted as an upwardly projecting pin 110, on an upper rail-grippingarm 112 of the depth stop 26 and a downwardly spring-biased rocker latch114 that snaps onto the upwardly projecting pin 110, preventinginadvertent retraction of the MRI biopsy device 14. The holster 44 maybe disengaged by downward pressure on a proximal actuating arm 116 ofthe rocker latch 114.

The single targeting rail 98 may be longitudinally sized to extendproximally ufficiently so that the MRI biopsy device 14 engages thesingle targeting rail 98 prior to the probe 100 contacting the patient'sskin. The single targeting rail 98 is also sized to not extendproximally to the extent that it would preclude use in a closed bore MRImachine (not shown). Such an MRI compatible biopsy system 10 is believedto minimize the procedure turn-around time to less than 45 minutes asdescribed above. However, despite the expeditious turn-around, aradiologist may position the probe 100 accurately to within 2 mm (5 mmmaximum) of the lesion center. Further, the radiologist may maximizeaccess to both breasts (left or right) during a procedure (both sides ofthe table) with minimal repositioning of the patient. Further, a minimalamount of force is needed to penetrate tissue, such as less than 4 lbs.Although the depth stop 26 serves to prevent overshooting, features forrepositioning the depth stop 26 prior to further insertion of the probe100 allow clinical flexibility in targeting another location.

In FIG. 4, an alternative guidance assembly 200 for the MRI compatiblebiopsy system 10 incorporates a cradle 202 that attaches to a targetingrail 204 and provides a biopsy rail 206 for supporting the MRI biopsydevice 14, both rails 204, 206 aligned to the Z axis. The targeting rail204 is attached to the positioning pillar 86 (not shown in FIG. 4) andis vertically adjusted to a desired Y-position. A circular attachmentpoint 208 may form a rotational engagement to the positional pedestal 86to allow an angled targeting guide.

A lateral face 210 of the targeting rail 204 includes an upper flange212 and a lower flange 214, each having an L-shaped cross section forslidingly receiving a sleeve mount 216. Vertical rows of laterallyprojecting ridges 218 in each flange 212, 214 serve as a locking surfacefor the sleeve mount 216. Between the flanges 212, 214, a side channel220 is recessed therein. The sleeve mount 216 guides a sleeve 222 byhaving its sleeve hub 224 proximally received in a hub receptacle 225 ofthe sleeve mount 216 and is distally positioned and constrained by adepth stop 226.

The depth stop 226 includes a slide member 228 that engages the sidechannel 220. A depth stop housing 230 attaches thereto, terminating in areticule 232. A locking lever 234 is vertically pinned within a distallyopen recess (not shown), defined in the depth stop 226 with a lateralportion 236 spring biased away therefrom such that distally projectingfeet 238 pivot against and engage the ridges 218, especially against aproximal movement. Depressing the lateral portion 236 proximally againstthe distally open recess of the depth stop housing 230 releases thedistally projecting feet 238 to allow repositioning the depth stop 226distally.

An axis of penetration of the biopsy device 14 is aligned with the axesdefined by the targeting rail 204 and the biopsy rail 206, which arelaterally and vertically orthogonally offset therefrom, respectively.Extending a horizontal plane from the targeting rail 204 and extending avertical plane from the biopsy rail 206 intersect at a common centerlinethat is the axis of penetration. Having the biopsy rail 206 verticallyaligned and parallel to the axis of penetration advantageously providessupport for the weight of the biopsy device 14 with a minimum of torsionloads that may otherwise create deflections of an inserted distal end.Thereby, even for a relatively heavy and elongated device, positioningand maintaining its distal end is achievable within 5 mm, and even 2 mm,of a desired insertion point. Thereby, a “hands free” procedure may beperformed. As an alternative, the cradle 202 below the axis ofpenetration pedestal 86 in the illustrative version may be replaced byone vertically displaced above the axis of penetration.

While a “hands free” capability is advantageous for a singleinsertion/multiple sample biopsy device, it should be appreciated thatsuch penetration guidance with a preset depth stop as described hereinhas application to even light-weight biopsy devices that employ a coreneedle biopsy with a single insertion per single sample. In particular,correct placement need not be conditional on continuous imaging. Overpenetration during insertion and inadvertent displacement is avoidedwhen hands are free.

A bottom dovetail channel 240 in the targeting rail 204 receives a topdovetail extension 242 on the cradle 202, which is slid therein. Itshould be appreciated that mounting is shown herein on the right side ofthe positioning pedestal 86 when viewed proximally, but that theguidance assembly 200 advantageously comprises symmetric parts thatallow mounting and use on either side of the positioning pedestal 86 toincrease flexibility in positioning the probe 100. Thus, a horizontalbase 244 of the cradle 202 forms the biopsy rail 206 as a biopsy guidechannel 246 flanked by a first and second pair of monocle receptacles248, 250 so that a pair of locking hooks 252 on a monocle 254 may beinserted in either pair of monocle receptacles 248, 250, depending onwhich is closer to the patient. Rather than mounting the cradle 202 tothe targeting rail 204 as depicted, a cradle may be directly attached tothe positioning pedestal 86 (not shown). The cradle 202 is mechanicallyrobust and can support the gross weight of the MRI biopsy device 14.Since the MRI biopsy device 14 does not share the cradle 202, the cradle202 may be optimized to support the MRI biopsy device 14 when eithershallow or deep lesions need to be accessed.

A guide bushing 256 inserted in a monocle reticule 258 guides a markinginstrument and/or a scoring scalpel (not shown) as an initial step inlocating and preparing an insertion point. The monocle 254 may beremoved thereafter or left in place to guide the sleeve 222 in additionto the reticule 232 of the depth stop 226, the latter which may alsohold a guide bushing 260 for guiding the sleeve 222. Removing the guidebushings 256, 260 allows for the reticules 258, 232 of the monocle 254and depth stop 226 to guide a larger component, such as a fiducial 262used for locating a suspicious lesion relative to the guidance assembly200.

The alignment of the sleeve 222 is maintained by first passing throughthe hub receptacle 225 of the sleeve mount 216, which receives thesleeve hub 224. In the illustrative version, the sleeve 222 has an openended shaft 266 for receiving an introducer obturator 268 that includesa piercing tip (e.g., flat blade) 270 at a distal end of solid obturatorshaft 272. A beveled recess 276 into the solid obturator shaft 272 isaligned with a sleeve side aperture 278 of the sleeve 222, and thusultimately of the probe 100 (FIGS. 1-3). The materials of the obturator268 may be selected to aid in locating the sleeve side aperture 278 ofthe sleeve 222, which otherwise may be more difficult to visualize andlocate in an MRI scan slice.

The sleeve hub 224 has its proximal cylindrical edge 280 attached to aguidance thumbwheel 282 that proximally extends from the hub receptacle225 of the sleeve mount 216 for rotating the sleeve 222 to position itssleeve side aperture 278 with reference to a visual mark, depicted as alocking slot 284, on the thumbwheel 282 corresponding thereto. Thethumbwheel 282 includes a central through hole 286 sealed by a wiperseal 288 and a duckbill seal 290 trapped between the thumbwheel 282 andthe proximal cylindrical edge 280 of the sleeve hub 224. Thus, insertionof the obturator 268, which includes a locking tab 292 that enters thelocking slot 284, closes the central through hole 286 and forms adynamic seal against the wiper seal 288.

After removing the obturator 268, a stylet 298 may be inserted into thesleeve 222 so that a proximally presented hose nib 300 of the stylet 298may be used to insufflate the surgical site or used for other purposessuch as draining bodily fluids or inserting therapeutic or diagnosticagents through a stylet shaft 302 of the stylet 298 to a stylet sideaperture 304 that is aligned with the side aperture 278 of the sleeve222. The stylet 298 also includes a locking tab 306.

The sleeve mount 216 includes a downwardly spring-biased rocker latch308 that snaps onto a ramped catch 310 on the depth stop 226, preventinginadvertent retraction of the sleeve 222. The sleeve mount 216 may bedisengaged by downward pressure on a proximal actuating arm 312 of therocker latch 308. An upwardly spring-based rocker latch 314, attached tothe bottom of the sleeve mount 216, similarly engages the depth stop226. Thus, after the depth stop 226 is set on the targeting rail 204 toa desired depth of insertion, the sleeve mount 216 may be distallyadvanced without overshooting and subsequently may be held in place whenremoving implements therefrom such as the obturator 268, stylet 298, andMRI biopsy device 14.

In FIG. 5, a further alternative guidance assembly 400 for the MRIcompatible biopsy system 10 includes a cradle 402 that engages a bottomchannel 403 of a primary targeting rail 404. To provide additionalguidance to the MRI biopsy device 14 of FIGS. 1-3, a secondary targetingrail 406 includes a lateral channel 408 that is guided along alongitudinal guide tab 410 of the primary targeting rail 404. When fullyengaged thereon, a pawl 412, pivoting under urging of a pawl spring 414about a vertical pawl pin 416 in a lateral window 418 proximallypositioned in the secondary targeting rail 406, drops into a proximaldetent 420 proximally positioned on the primary targeting rail 404.

A sleeve 422 includes a hollow shaft (or cannula) 423 that is proximallyattached to a cylindrical hub 424 and has a lateral aperture 426proximate to an open distal end 428. The cylindrical hub 424 has anexteriorly presented thumbwheel 430 for rotating the lateral aperture426. The cylindrical hub 424 has an interior recess 432 that encompassesa duckbill seal 434, wiper seal 436 and a seal retainer 438 to provide afluid seal when the shaft 423 is empty and to seal to an insertedintroducer obturator 440.

The introducer 440 advantageously incorporates a number of componentswith corresponding features. A hollow shaft 442 includes a fluid lumen444 that communicates between a side opening 446 and a proximal port448. The hollow shaft 442 is longitudinally sized to extend a piercingtip 449, when fully engaged, out of the distal end 428 of the sleeve422. An obturator thumbwheel cap 450 encompasses the proximal port 448and includes a locking feature 452, which includes a visible angleindicator 454, that engages the sleeve thumbwheel 430 to ensure that theside opening 446 is registered to the lateral aperture 426 in the sleeve422. An obturator seal cap 456 may be engaged proximally into theobturator thumbwheel cap 450 to close the fluid lumen 444. The obturatorseal cap 456 includes a locking feature 458 that includes a visibleangle indicator 459 that corresponds with the visible angle indicator454 on the obturator thumbwheel cap 450.

The sleeve 422 is guided, during penetration of tissue, by a sleevemount 460 having a sleeve hub 462 that receives the cylindrical hub 424of the sleeve 422. The sleeve mount 460 has a lateral sleeve hub channel464 that slides along top and bottom guide flanges 466, 468 of thesecondary targeting rail 406, each having an aligned and recess ridged,ratcheting surface 470 that interacts with a respective top and bottomratcheting feature 472, 474 on respective top and bottom rail lockrocker latches 476, 478 that are engaged by respective top and bottomlatch pins 480, 482 in respective sides of the sleeve mount 460. Theratcheting features 472, 474 are proximally ramped such as to allowdistal movement. Distal portions of each rail lock rocker latches 476,478 are biased away from the sleeve mount 460 by respective rail lockcompression springs 484, 486 to bias the ratcheting features 472, 474into contact with the ridges surfaces 470 of the guide flanges 466, 468.Simultaneous depression of the rail lock rocker latches 476, 478 allowthe sleeve mount 460 to be drawn proximally, withdrawing any sleeve 422supported therein, until the sleeve mount 460 reaches a proximal end ofthe secondary targeting rail 406, whereupon the sleeve mount 460 rotatesthe pawl 412 clockwise (as viewed from the top) and is thus engaged tothe secondary targeting rail 406 as the secondary targeting rail 406 isunlocked from the primary targeting rail 404, causing removal therefromwith continued proximal movement.

Before mounting the secondary targeting rail 406 onto the primarytargeting rail 404 in the first place, the sleeve mount 460 isadvantageously adjustably positioned on the secondary targeting rail 406to set a desired depth of penetration. In particular, a depth guide 490is formed by a crescent-shaped depth indicator 492 having a lateralchannel 496 shaped to engage the top and bottom guide flanges 466, 468.Forward ramped surfaces 498 on the top and bottom of the lateral channel496 are positioned to engage the ridged ratcheting surfaces 470 on thesecondary targeting rail 406, allowing assembly by inserting the depthindicator 492 from a distal end of the secondary targeting rail 406.Frictional engagement thereafter resists further proximal movement andstrongly opposes any distal movement, especially from a depth lead screw500 of the depth guide 490, whose distal end 502 rotates within anoutboard hole 504 in the depth indicator 492 and whose proximal enddeflects laterally as a depth actuator lever 505 is used to rotate andlongitudinally position the depth lead screw 500 therein. A mid portionof the depth lead screw 500 is received in a longitudinal through hole506 formed in the sleeve mount 460 outboard to its lateral channel 408.For coarse depth adjustment, outer lead threads 507 on the depth leadscrew 500 selectively engage the sleeve mount 460 until top and bottomcoarse adjust buttons 508, 510 are inwardly depressed into the sleevemount 460, compressing respective top and bottom coarse adjustcompression springs 512, 514. Each coarse adjust button 508, 510includes a respective vertically elongate aperture 516, 518 whose inwardsurface presents a worm gear segment 520, 522 to engage the outer leadthreads 507 on the depth lead screw 500 when urged into engagement byrelaxed coarse adjust compression screws 512, 514.

In two U.S. patent aplications entitled “AN MRI COMPATIBLE BIOPSY DEVICEWITH DETACHABLE PROBE”, to Ifibner et al., Serial In theabove-referenced U.S. patent application Ser. No. 10/170,535, filed on23 Apr. 2002, and published on 23 Oct. 2003 as Pub. No. US 2003/0199753,and entitled “MRI BIOPSY DEVICE”, Ser. No. 11/076,612, filed 10 Mar.2005, the disclosure of both of which are hereby incorporated byreference in its entirety, a detachable probe (or sleeve) is describedthat has a number of advantages, such as allowing MRI procedures to beperformed with the probe remaining inserted during reimaging. In FIGS.1-5, a separate sleeve and obturator capability provides even additionalclinical flexibility. It should be appreciated, that variouscombinations of features may be selected for specific applications orpreferences. Having a side aperture in a sleeve, corresponding to asample-taking side aperture in the biopsy device, is often desirable.For instance, an open ended probe or biopsy needle that is inserted bynecessity into a suspicious lesion may create hematomas that fill withresidual contrast agent making it difficult to perform further imagingstudies at that site. For another, piercing a suspicious lesion may posea risk of track metastasis. Further, the tip of such a needle or probemay be difficult to image with respect to the suspicious lesion toaccurately locate the latter, being essentially a point.

By contrast, in FIG. 6, a side aperture 600 of a sleeve 602 may bepositioned beside a suspicious lesion so that a piercing tip 604 neednot pass through the suspicious lesion. Locating this side aperture 600in an MRI scan slice would seem to be easier in that the side aperture600 defines a line that more readily allows orienting an imaging slicealong its length with a geometric reference that readily shows from whatdirection tissue may be drawn into the side aperture 600 for biopsying.However, slices that are not ideally oriented or that pass through MRIcompatible materials that may form the sleeve 602 may still complicateaccurate and expedient identification of the side aperture 600. Toassist in this identification, an obturator 606 assists duringintroduction of the sleeve 602 by substantially or completely blockingthe side aperture 600 so that tissue does not prolapse into the sideaperture 600 and impede insertion and/or cause tissue trauma.

In some applications, it is further desirable to have a distal opening608 in the sleeve 602. The obturator 606 thus advantageously includesthe piercing tip 604 that extends distally out of the distal opening 608in the sleeve 602. The obturator 606 further has a lateral recess (e.g.,notch, bevel, canoe dug-out) 610 aligned with the side aperture 600 inthe sleeve 602 when the obturator 606 is fully inserted therein. Beingradially asymmetric, this lateral recess 610 provides a rapidly acquiredand interpreted reference for locating the side aperture 600.

In FIG. 7, a side aperture 620 is formed in a sleeve 622 that has aclosed distal end 628 that forms or supports a piercing tip 624. Anobturator 626 serves to shape the prolapse of tissue into the sideaperture 600 during introduction and includes a lateral recess (e.g.,notch, bevel, canoe dug-out) 630 aligned with the side aperture 620 inthe sleeve 622 when the obturator 626 is fully inserted therein.

In FIG. 8, an obturator 646 includes a piercing tip 644 that extends outof the distal opening 608 in the sleeve 602 of FIG. 6. The obturator 646creates a distinctive cross section by having an upper longitudinalportion 649 and a lower longitudinal portion 651. The upper longitudinalportion 649 is shaped to control the prolapse of tissue into the sideaperture 600 as well as present a readily located reference for an MRIscan slice.

In FIG. 9, the sleeve 622 of FIG. 7, with the closed distal end 628formed into or supporting the piercing tip 624, is shown having its sideaperture 620 closed during introduction by an obturator 656 having adistinctive cross section showing an upper longitudinal portion 659 anda lower longitudinal portion 661. The upper longitudinal portion 649 hasa cross sectional profile that is designed to shape the prolapse oftissue into the side aperture 620 as well as present a readily locatedreference for an MRI scan slice.

In FIG. 10, a sleeve 702 has a side aperture 700 and a closed distal end708 which are formed into an asymmetric piercing tip 704 thatencompasses an obturator 706. The obturator 706 has a continuous profileformed by an upper longitudinal portion 709 and a lower longitudinalportion 711 that create a distinctive cross section, such as an X-shapeas depicted in FIGS. 11-12. Alternatively, the obturator 706 may have adistinctive cross section such as an upward longitudinal spine 715attached to a lower longitudinal half-cylinder 717 as depicted in FIGS.13-14. It should be appreciated that the prolapse of tissue at the sideaperture 700 provides an MRI image return whereas in other portions ofthe obturator 706, the air spaces between the sleeve 702 and theobturator 706 appear similarly dark.

In FIG. 15, an obturator 806 includes a lateral notch 810 proximate to apiercing tip 804. Rather than relying upon tissue prolapsing underforces of gravity, palpation or vacuum assist, an MRI visible insert 807(e.g., an aqueous gel).may advantageously have sufficient stiffness toremain in place and to prevent prolapse of tissue into a side apertureof a sleeve (not shown in FIG. 15). In FIG. 16, instead of beinglaterally inserted, an obturator 826 may include a proximally accessedmarker lumen 827 through which a marker insert 829 may be insertedproximate to a distal piercing tip 824.

As an alternative to an added MRI visible material, in FIG. 17, anobturator 846 includes a vacuum lumen 848 that communicates with alateral notch 850 to draw in sufficient bodily fluids 851 to present anMRI visible image of the side aperture of the sleeve (not shown). InFIG. 18, the obturator 846 employs vacuum assist through the vacuumlumen 848 to prolapse tissue 853 into the lateral notch 850 to presentan MRI visible image. In FIG. 19, the obturator 846 further includes athin sheath 855 that is slid overtop of the lateral notch 850 to capturean MRI visible material (e.g., aqueous fluid, gadolinium solution, etc.)857.

In FIG. 20, an obturator 876 includes a solid stylet insert 879substantially encompassed by a cylindrical sheath 877, except for over alateral notch 881 formed in the solid stylet insert 879. The cylindricalsheath 877 is distally attached to a ceramic asymmetric piercing tip874.

In FIG. 21, an obturator 896 has an open distal end 894 and a lateralaperture 890 with vacuum assisted air evacuation proximally from amarker lumen 893 formed therein, allowing the marker lumen 893 to fillwith bodily fluids to present an MRI visible material.

In FIG. 22, an obturator 906 has a piercing distal end 0904 and alateral aperture 0900 with vacuum assisted air evacuation to allow amarker lumen 903 to fill with bodily fluids to present an MRI visiblematerial.

In FIG. 23, an obturator 916 has a closed, blunt distal end 914 and amarker lumen 918 containing an MRI visible material (e.g., gadoliniumsolution, aqueous solution) 911. An MRI dark plug 913 (e.g., collagen,nonferrous metal, plastic) is positioned to correspond to a sideaperture of a sleeve (not shown in FIG. 23). The MRI dark plug 913contains longitudinal fluid leak passages 915 to allow MRI bright imagesto be formed to each side of the side aperture within the marker lumen918.

In FIG. 24, an obturator 926 has a piercing distal end 924 and a markerlumen 928 containing an MRI visible material (e.g., gadolinium solution,aqueous solution) 921. An MRI dark plug (e.g., collagen, nonferrousmetal, plastic) 923 is positioned to correspond to a side aperture of asleeve (not shown in FIG. 24). The MRI dark plug 923 containslongitudinal fluid leak passages 925 to allow MRI bright images to beformed to each side of the side aperture within the marker lumen 928.

In FIG. 25, an obturator 936 has a piercing distal end 934 and a markerlumen 938 containing an MRI visible material (e.g., gadolinium solution,aqueous solution) 931. A side aperture 930 communicates with the markerlumen 938 via fluid leak passages 935 formed in an MRI dark plug (e.g.,collagen, nonferrous metal, plastic) 933 otherwise blocking the markerlumen 938.

In FIGS. 26-37, further illustrative versions of the shape of a sleeveand obturator are depicted that advantageously enhance the ability tolocate suspicious lesions and to confirm proper placement of the sideaperture thereof prior to taking biopsy samples by presenting a closedshape during penetration that may be changed to a shape that correspondsto a relieved area where samples will be taken, this shape visibly solidso as to be readily recognizable even when viewed from various angles ofimaging slices.

This feature addresses drawbacks from relying upon the probe forimaging. Having a metallic substance in the imaging field may cause anartifact (local blooming) that may obscure the tissue of interest, suchas attempting to use the biopsy probe itself to obturate the sleeve.Removing the probe during imaging and relying upon only the sleeveallows another imaging challenge to occur as an imaging slice throughthe hollow sleeve 22 may pose difficulties in identifying the sideaperture. Often, the MRI compatible material selected gives no MRIreturn image, just as an air-filled void present across a side aperturethus presenting no return.

In FIGS. 26-27, an MRI compatible biopsy system 1210 includes a sleeve1222 having a notch 1202 that corresponds to the location and size ofthe probe side aperture of the probe of the MRI biopsy device (not shownin FIG. 26). Moreover, the depth of the notch 1202 may be deeper thanthe probe side aperture in some instances to accentuate this location onthe sleeve 1222 for imaging purposes.

An obturator 1224, shown in phantom in FIG. 26 in its “closed position”substantially blocking the notch 1202 of the sleeve 1222, may beadvantageously formed of a thermoplastic as described with a distallypresented ceramic bladed portion 1220 that extends through an opendistal end 1221 of the sleeve 1222. Ceramic materials perform well in anM environment and hold a sharpened edge. With the notch 1202 closed bythe co-axially inserted obturator 1224, the sleeve 1222 may be insertedinto breast tissue.

In FIGS. 28-29, the obturator 1224 depicted advantageously includes alongitudinally bifurcated design as shown in FIGS. 28-29 wherein thelower portion 1223 includes a dovetail channel 1225 down its length thatslidingly engages a dovetail tab 1227 extending down from an upperportion 1229 of the obturator 1224. The ceramic bladed portion 1220 isattached only to the lower portion 1223. As shown in FIG. 28, the upperportion 1229 may be proximally moved with the lower portion 1223 fullydistally inserted into the sleeve 1222 to thereby open the notch 1202 ofthe sleeve 1222. Since the obturator 1224 is solid, during the 3-4 mmimage slices taken by the MRI machine, the lower portion 1223 of theobturator 1222 fills in the notch 1202 SO that its location may bereadily ascertained. This two-piece obturator 1224 advantageouslyaccommodates sleeve lumens with complex cross sectional shapes, such asthe depicted oval-shaped sleeve 1222 (FIG. 27).

In FIGS. 30-31, a sleeve 1322 includes an integral sharp 1320 distallyattached to its shaft 1319 that defines a circular cutter lumen 1321 andan underlying vacuum lumen 1323 (FIG. 31). In FIGS. 32-33, a roundobturator 1324 is generally rod-shaped for insertion into the cutterlumen 1321 but with a notch recess 1325 formed corresponding to a notch1302 of the sleeve 1322 (FIG. 30). Insofar as the round obturator 1324is rotatable within the cutter lumen 1323, the notch recess 1325 may beselectively presented to open the notch 1302 in the sleeve 1322 orrotate about half a revolution to close the notch 1302.

The resulting effect in an MRI image scan is illustrated in FIGS. 34-35wherein selectively closing the notch 1302 in the sleeve 1322 with theobturator 1324 presents a solid image but with little indication ofwhere the notch 1302 is oriented. In FIGS. 36-37, with the obturator1324 rotated to open the notch 1302, it is readily apparent where thenotch 1302 is oriented.

As an alternative to a latch locking feature between an obturator 1424and a sleeve 1422, as described above for FIGS. 4-5, in FIG. 38, theobturator 1424 may selectively proximally attach to the sleeve 1422 toprevent inadvertent retraction and to assist maintaining apneumatic/fluid seal with a bayonet-style attachment 1430 formed bycleats 1432 radially projecting from a cylindrical base 1434 of theobturator 1424 that is received within L-shaped recesses 1436 registeredwithin a proximal bore 1438 of a sleeve lumen 1440 of the sleeve 1422.In FIG. 39, a threaded attachment 1450 is formed by male threads 1452about a cylindrical base 1454 of an obturator 1424 a that is threadinglyreceived by female threads 1456 about a proximal bore 1458 of a sleevelumen 1460 of a sleeve 1422 a. In FIG. 40, a button release attachment1470 is formed by locking hooks 1472 radially exposed about acylindrical base 1474 of an obturator 1424 b that are asserted into aproximal bore 178 of a sleeve lumen 1480 of a sleeve 1422 b. The lockinghooks 1472 engage a ramped recess 1481 in the proximal bore 1478,holding the obturator 1422 b in its distal longitudinal position. Foreach locking hook 1472, a respective one of a pair of buttons 1476extends through a respective ramped recess 1481, initially forcedoutward upon insertion of the locking hooks 1472. A user may depress thebuttons 1476 while exerting a proximal pressure on the obturator 1424 bto disengage the locking hooks 1472.

Additional therapeutic and diagnostic abilities are provided by use of asleeve that is separate and apart, but is used in conjunction with anMRI biopsy device. This utility is enhanced by incorporating fluid andpneumatic seals within the sleeve so that bodily fluids may beselectively drained, anaesthesia or other medical compounds may beinserted into the surgical site of the biopsy, insufflation or deflationof the surgical site may occur, and/or vacuum assist of the MRIcompatible biopsy system may be maintained.

In FIGS. 41-42, a sleeve 1522 incorporates a full-diameter seal, orseptum 1523, across a proximal bore opening 1524 to a sleeve lumen 1526.Thereby, without an obturator, stylet or probe of an MRI biopsy deviceinserted coaxially in the sleeve 1522, a degree of pneumatic pressure(e.g., insufflation) may be maintained in the breast tissue and/or leaksof fluid prevented. The sleeve 1522 advantageously incorporates a port1530 in its base that communicates with a distal portion 1528 of thesleeve lumen 1526 to a side aperture 1502 for purposes such as drainingfluids or adding anaesthesia.

In FIGS. 43-44, a similar sleeve 1522 a incorporates an O-ring dynamicseal 1550 instead of the full-diameter seal that forms a seal with anobturator 1524, which may advantageously include a groove or passage1552 down its length to allow fluid communication between the port 1530and side aperture 1502.

In FIGS. 45-46, a similar sleeve 1522 b incorporates a more distalO-ring dynamic seal 1560 and port 1562 to the proximal O-ring dynamicseal 1550 and proximal port 1530. An obturator 1524 b may advantageouslyhave two grooves or passages 1570,1572 that communicate between arespective port 1530, 1562 and a respective side aperture 1502 and opendistal end 1574.

With reference to FIG. 47, an obturator 1600 includes a sharp piercingtip 1602 that is advantageously shielded when not being employed topierce tissue by a cylindrical sheath 1604. Thereby, the hazard ofinadvertent injury and equipment damage is mitigated. In FIG. 48, as theobturator 1600 is inserted through a sleeve 1606, the cylindrical sheath1604 passes through a seal retainer 1608 and is captured within aduckbill seal 1610 held between the seal retainer 1608 and a sleeve hub1612. The piercing tip 1602 passes on through the sleeve hub 1612 and onthrough a cannula 1614 of the sleeve 1606. It should be appreciated thatupon retraction of the obturator 1600, the piercing tip 1606 passes intothe sheath 1604 and draws the sheath 1604 out of the sleeve hub 1612.

In FIGS. 49, 49A, an alternate obturator 1630 has a sharp piercing tip1632 selectively shielded by a sheath 1634 that may be stowed proximallyin a cylindrical relieved area 1636 so that the sheath 1634 conforms toan outer diameter of a shaft 1638 of the obturator 1630. A proximalcontrol (not shown) actuates the sheath 1634 distally, either whileinside of a sleeve 1640 as depicted or when the obturator 1630 isremoved therefrom. The piercing tip 1632 is depicted as including a flatcutting blade 1642 that, at its base, extends the full diameter of theobturator shaft 1638. Thus, a distal portion 1644 of the sheath 1634 issplit to pass on either side of the flat cutting blade 1642 (FIG. 49A).

The sleeve may be formed advantageously of a polymeric material, eitherhomogenous or a composite, that is strong yet with thin walls so thatthe overall outer diameter need not be significantly larger than knownbiopsy probes, thereby being minimally invasive. The strength and smallcross sectional area minimizes the size of the opening through the skinand thus typically avoids the need for sutures to close, reduces theforce required to insert the probe, and minimizes trauma to breasttissue penetrated enroute to a suspicious lesion. The strength andrigidity advantageously maintain an open lumen for subsequent biopsy andother procedures therethrough. In addition, the sleeve is advantageouslyformed from materials that are biologically compatible to the patientand MRI compatible. Generally, the material thus does not createsignificant imaging artifacts that would obscure tissue images proximateto the sleeve 22.

Examples of polymeric materials that may be used, although not an allinclusive list, include polyimide, polyetherimides (e.g., ULTEM® resinby GE PLASTICS), thermoplastic liquid crystal polymers (LCP) (e.g.,VECTRA® by CELANESE AG), polyethylether ketones (e.g., PEEK™ by VITREX),polyamide, polycarbonate (e.g., MAKROLON by BAYER POLYMERS),polysulfone, polyethersulfone, polyphenylsulfone (e.g., RADEL® byROWLAND TECHNOLOGIES), and nylon and nylon copolymers.

In FIGS. 50-54, an obturator 1660 with a piercing tip 1662 has aprotective sheath 1664 drawn proximally by interference with a sleevehub 1666 of a sleeve 1667 (FIG. 50). Inward guide ridges 1668 of aproximal portion of the sheath 1664 move along guide slots 1670 formedin a shaft 1672 of the obturator 1660. A distal portion of the sheath1664 includes a plurality of radially spaced longitudinal slits 1674 toform a plurality of protective flaps 1676 (e.g., four flaps in FIG. 51and three flaps in FIG. 52) that are biased to deflect toward thelongitudinal centerline when not held out by the shaft 1672 (FIG. 53).The inward bias of the protective flaps 1676 may be imparted to thesheath 1664 formed of spring metal, molded polymer, shape memory alloyannealed in closed position, etc.

In FIG. 55, a piercing member (e.g., probe, multi-function obturator)1700 has piercing tip 1702 as described below with regard to FIGS.77-80B. A lateral notch 1704 is accentuated by an underlying MRI visiblemarker 1706 and communicates with a lumen 1708 that may be used foraspiration, hemostasis, introduction of anesthesia or pharmacologicalcompound, and/or a marking material. Leading and trailing edges 1710,1712 of the lateral notch 1704 are rounded so as to avoid trauma totissue during insertion and retraction.

In FIG. 56, an alternate piercing member 1730 has a pair of MRI visiblemarkers 1735, 1736 that flank a lateral notch 1734 with a lower lumen1738 aligned to terminate below the lateral notch 1734 and tocommunicate thereto via holes 1740. Thereby, imagability and fluidintroduction/extraction is facilitated by the piercing member 1730.

In FIG. 57, a combination of the features of FIGS. 55-56 is shown with afurther alternate piercing member 1760 having a pair of MRI visiblemarkers 1765, 1766 that flank a lateral notch 1764. A marker lumen 1768is aligned to enter a trailing edge 1770 of the lateral notch 1764 witha leading edge 1772 of the lateral notch 1764 ramped to eject a toolsuch as an inserted marker deployment tool 1769. A lower lumen 1771terminates below the lateral notch 1764 and communicates thereto viaholes 1775 for insufflation during marker deployment or for transferalof fluids.

In FIG. 58, a core needle 1800 having a lumen 1802 aligned to alongitudinal centerline thereof communicates to an open distal end 1804for deploying core biopsy tools, a marker tool, wire for localization,an ablation device, etc. An imagable marker 1806 advantageouslysurrounds the open distal end 1804 to assist in proper placement of thecore needle 1800.

In FIG. 59, an obturator 1830 includes a distal opening 1832 and a sidedeployment opening 1842 that selectively communicates with alongitudinal lumen 1836 with an adapter sheath 1840 that aligns the sidedeployment opening 1842 with a side aperture 1844 in a sleeve 1846,directing deployment of a tool 1848 through the side aperture 1844. InFIG. 60, the adapter sheath 1840 is rotated to misalign the sidedeployment opening 1842 with the side aperture 1844 of the sleeve 1846,directing deployment of the tool 1848 through the distal opening 1832.

In FIG. 61, a curl-biased tool 1870 is shown rotated to upward adeflected tip 1872. The curl-biased tool 1870 is inserted into anobturator 1874 in FIG. 62 with the deflected tip 1872 aligned such thetool 1870 is allowed to pass through a lumen 1875 to a side deploymentguide 1876 aligned with a lateral aperture 1878 in a sleeve 1880. InFIG. 63, the curl-biased tool 1870 is rotated a half rotation to orientthe deflected tip 1872 downward. When inserted into the obturator 1874in FIG. 64, the tool 1870 deploys out of a distal opening 1882.

In FIG. 65, an obturator 1900 includes a side opening 1902 and a distalopening 1904 of a lumen 1906. A distally-moving diverting member 1908 isramped across the lumen 1906, aligned to guide a tool 1910 toward theside opening 1902, and thus extending out a lateral aperture 1912 of anencompassing sleeve 1914. Retracting the diverting member 1908 in FIG.66 opens up the lumen 1906, allowing the tool 1910 to extend out of thedistal opening 1904.

In FIG. 67, an obturator 1940 includes a side opening 1942 and a distalopening 1944 of a lumen 1946. A plug 1948 may be inserted into thedistal opening 1944, configured such that a proximal end 1949 is rampedand aligned with the side opening 1942 to guide a tool 1950 toward theside opening 1942, and thus extending out a lateral aperture 1952 of anencompassing sleeve 1954. Removing the plug 1948 (not shown) opens upthe lumen 1946, allowing the tool 1950 to extend out of the distalopening 1944.

In FIGS. 68-70, a sleeve 2000 with an open distal end 2002, a sideaperture 2004, and a proximal septum or seal 2006 encompassed by asleeve hub 2008 is shown. In FIG. 68, during penetration andguidance/confirmation imaging, an obturator 2010 is inserted into thesleeve 2000 with a seal formed therebetween by the seal 2006. Theobturator 2010 provides a penetrating tip 2012 and an imagable sidenotch 2014 accentuated with an underlying marker 2016. In FIG. 69, amarker stylet 2020 is inserted into the sleeve 2000 and sealed therein.The marker stylet 2020 includes a side notch 2022 accentuated by anunderlying marker 2024 that communicates with a lumen 2026 thatproximally terminates in a leur fitting 2028, selectively sealed by ahandle cap 2030 or attached to various pneumatic or fluid handlingconnections. In FIG. 70, a wire localizer/core needle stylet 2040 isinserted into the sleeve 2000 and sealed therein. A lumen 2042communicates between a distal opening 2044 and a proximal leur fitting2046. A marker ring 2048 about the distal opening 2044 assists inconfirmation imaging.

In FIG. 71, a polyimide process may be used to form this materialwherein a film is formed from solution. A standard practice is to coatcontinuous wire by passing wire from a spool, through a polyimidecoating solution through a furnace to a take-up spool. The wire usuallygoes through multiple processes to build up the coating thickness. Theinline furnace or heating element drives off the solvent and causespartial cross-linking of the polyimide. Full cross-linking occursusually when the desired coating thickness has been achieved. The fullcross-linking temperature occurs at a much higher temperature than thetemperature used during coating.

To create the free standing polyimide tube, the wire is then removed.For example, lengths of the coated wire may be cut with the wire pulledor drawn from both ends to stretch it, thereby reducing its outerdiameter until separated from the coating, then withdrawing the wire.Alternatively, an easily chemical etched material may be used for thewire. For instance, a cooper wire may be dissolved by a persulfatecomplexing solution leaving behind a free standing polyimide tube.

Further, to create more complex cross sectional shapes (FIG. 72A-72D)(e.g., oval, etc.) the polyimide tube may be placed in a form prior to afinal cross-linking heat step. In addition, a mandrel may be insertedthrough the polyimide tube to further define the shape, especially incooperation with compressing outer forms, such as depicted in a sequenceof FIGS. 73A-73C for an oval and in a sequence of FIGS. 74A-74E for awaisted oval.

In FIGS. 75, 76A-76B, follow-on processes to create a side aperture atits distal end and/or mounting holes at its proximal end may then beformed. For instance, laser cutting by an eximer or YAG laser may formdesired perforations. Further, an eximer laser may not be used to formthrough holes but also reliefs sufficient to create enough mechanicalinterference with over-molded parts to ensure assembly integrity duringnormal loading and tension. Full perforations may be used to allow anover-molded part, such as proximal end mounting mechanisms, to flowthrough the holes before hardening.

To achieve holes in the tube of FIG. 75, several methods may beemployed. For instance, an eximer or YAG laser machine may create theperforations (FIG. 76A). The eximer laser may also be programmed tocreate not only through holes, but also reliefs. Reliefs may besubstituted to create sufficient mechanical interference with anovermolded part to ensure assembly integrity during normal loading andtension (FIG. 76B). As another example, a punch or die-cut process maybe integrated into the forming mold. The parts may be cut, trimmed andpunched followed by heat treatment in the same form.

The forming molds advantageously should be both hard and have highthermal conductivity. Steel, while hard, has low thermal conductivity.Copper and brass, by contrast, have high thermal conductivity, but aresofter. An alloy of hardened aluminum may be a suitable material for theforming molds with steel inserts for punching holes.

A sheath may also be formed from a braided composite. Individual fibersof the braid may be wound on an initial layer of polyimide and thensealed in a layer of polyimide. The braid may be of an MRI compatibleceramic fiber, such as NEXTEL by 3M.

Portions of the sleeve and/or obturator may be formed from materialschosen for their imagability, either dark or bright. Under most standardMRI scan sequences used to image breast tissue for possible cancer,known engineering plastics appear dark or have low contrast, which maycause problems when identifying such components for localizing anddiagnostic purposes. Consequently, in addition to considerationsdescribed above when forming a sleeve of sufficient strength and MRIcompatibility, it may be advantageous to substitute or augment materialthat is bright to an MRI machine but that does not create a significantartifact. In addition or as an alternative, an overmold or coat orinsert material that appears bright to an MRI machine may be formed overstructural “dark” material. In addition or as an additional alternative,a “dark” material chosen for strength or other reasons may be overmoldedor coated or inserted with materials that absorb a contrast enhanced orbright fluid. In addition or as yet another alternative, a composite ormultilayered material may be formed with some layers chosen forproperties such as strength and others chosen for their characteristicof being visible to the MRI machine.

Particular patterns of marker bands, for instance, may be placedinferior to the side aperture of the sleeve, or in spaced rings proximalto or distal to the side aperture about the sleeve. As an example, Dy₂O₃or Fe_(2 O) ₃ may be mixed with an ink and then printed onto portions ofthe sleeve 22 or used to fill recessed grooves on the obturator 24 orstylet. Such patterns may also be created by dispersing Dy₂O₃ or Fe₂O₃as filler into a thermoplastic so that isit may be applied to the sleeve24 and/or obturator by reflow or thermal bonding. Yet another approachis to insert mold Dy₂O₃ or FC₂O₃ into the device, such as by loading amolded/extruded component plastic (e.g., PEEK, ULTEM) and attach (e.g.,over mold a ring of 30% Dy₂O₃ in PEEK).

As yet a further alternative, regions of material may be capable ofbeing infused or hydrated with a water based solution and/or a contrastagent (e.g., gadolinium chelate) that would thus appear bright whenimaged. As yet another alternative, regions of material, such asinfusion or hydration, may occur immediately before use or such materialmay be pre-hydrated and aseptically packaged.

In particular, certain polymers that appear bright to an MRI machine maybe selected to include synthetic water soluble polymers that have highalcohol or carboxilic acid functionality. For example, cellulosederivatives include carboxymethyl cellulose, ethyl cellulose,hydroxyethyl cellulose, carboxymethyl hydroxyethyl cellulose,ethylhydroxyethyl cellulose, and methyl cellulose. As another example,acrylates include polyacrylic acid salts and polyacrylamide. For yetanother example, other artificial materials include polyvinyl alcohol(PVA), polyvinyl methyl ether, polyvinylpyrrolidone (PVP), andpoly(ethylene) oxide (PEO). As yet a further example, natural productsand derivatives include cornstarch, gelatin, dextrins, alginates,casien, collagen (e.g., bovine, etc.) and natural gums (e.g., xanthum,tragacanth, karaya, etc.). As yet an additional example, biopolymersinclude polylactic acid, di-lactide-co-glycolide (PLG) (i.e., as anexample of lactide isomers (D, L, DL) (MP=225-230° C.)),polycaprolactone (MP=60° C.), lactates and gluconates, polydioxanone,polyglactin (i.e., suture materials).

Other polymers that appear bright to an MRI machine include siliconebased materials such as siloxanes functionalized with hydroxyl (—OH)groups and carboxylic acid groups and such as silicones (i.e., bothfluid and gum rubbers).

In an illustrative version when making polymeric materials image withoutexcessive artifact in MRI, dysprosium oxide (Dy₂O₃) or hermatite (Fe₂O₃)was dispersed as a filler in a thermoplastic carrier that can bethermoformed (e.g., extruded, molded, etc.). A marker thus formed, whenintegrated into a device such as the sleeve 22 or obturator 24, improvesdevice visibility under MRI (e.g., gradient echo EPI, flash, real-timetrue FISP). In particular, Dy₂O₃ (35%) was dispersed in Rilsan®Polyamides (75%) ATOFINA Chemicals, Inc. This combination was extrudedinto thin-walled (i.e., 0.002 inch) tubing, which was quite visibleusing Flash. Further, Flash appears to create the best visibility forsusceptibility devices (includes Dy₂O₃ and Fe₂O₃), EPI was less visible,and real-time true FISP was not visible.

Other polymers that appear bright to an MRI machine include hydrophilicpolymer and polymeric foams such as urethane foams that rapidly absorbmoisture when adding hydrophilic block-copolymer segments are added intothe urethane backbone or use surface functionalization such as thateffected by plasma oxidation or chemical oxidation. Similarly, otherpolymers may be foamed such as starch with linear low densitypolyethylene, expanded polytetrafluoroethylene (PTFE), or othermaterials (e.g., polyimides, polyolefins, polystyrenes, polyesters,nylons, acrylics, acrylates, polycarbonates, melamines,polyvinylchloride, polyvinylacetate).

As implementations wherein aqueous based solutions are infused orhydrated into such materials, such solutions include gadolinium basedcompounds for T1 enhancement in solution including diethylenetriamenepentaacetic acid (DTPA), gadoteridol (GD-HP-D03A) (nonionic),gadodiamide (GD-DTPA-BMA) (nonionic), and GdDOTA (ionic). Such solutionsalso include iron-based solutions for T2 enhancement such as Feridex(super paramagnetic agent).

Accentuating the side aperture 102 of the sleeve 22 has been discussedabove as in the choice of materials or shaping of the obturator thatselectively closes the side aperture 102. It is also mentioned abovethat specific regions of the sleeve 22 may be accentuated. With regardto the latter, marking the side aperture 102 with material that isbright under MRI imaging may be accomplished with commercially availablecontrast agents to leverage existing capital equipment and supplychannels. Examples of such contrast agents are gadolinium (Gd⁺³) (e.g.,MAGNEVIST® (gadopentetate dimeglumine) by BERLEX); iron (Fe⁺³) (e.g.,FERIDEX IV® (ferumoxides injectable solution); and manganese (Mn⁺²)MnDPDP (e.g., TESLASCAN™ Mangafodipir by AMERSHAM HEALTH). A matrix of apolymer may swell in the presence of water to create a contained,hydrated environment for the contrast agent. These polymers would bepermeable to water, but have limited permeability of the contrast agentmolecules. The contrast agents may be chemically bound to the matrix toreduce or limit their migration out of the matrix. Examples of polymerssuitable for such a matrix include hydrogels, urethane acrylates withhydrophilic blocks, latex paints/emulsions, coatings loaded withhydrophilic particulate such as silica particles and particleagglomerates.

A void within an obturator may include a vent and a septum. Contrastagent may be injected through the septum with air vented through thevent. Hydrophilic foam or cellulose material (e.g., cotton) within thevoid may be used to better retain the contrast agent. Alternatively,contrast chelate may be preloaded onto the hydrophilic foam or cellulosematerial and hydrated during the procedure.

As an alternative or an addition to materials that are bright under MRI,active marker band technologies may be incorporated to illuminate a sideor distal aperture in the sleeve 22. Examples of active illuminationused in different applications are described in U.S. Pat. Nos.5,211,165; 5,307,808; 5,318,025; 5,437,277; 5,443,066; 5,445,150;5,715,822; 5,882,305 and 6,289,233. Coils are formed proximate to thesampling aperture, such as side aperture 102 with electrical connectionsformed along the length of the sleeve 22. Polyimide is a particularlygood material choice for forming a substrate for such coils andelectrical connections because of significant development of technologyand processes to form thin film electronic circuits on polyimide.Electrical isolation may be achieved with overcoats of another layer ofpolyimide. An inductive coil about the base of the sleeve 22 that is inelectrical communication with these marker bands would allow RF couplingto these coals and provides RF isolation for the patient. Alternatively,a dedicated integrated circuit and power source (e.g., battery,capacitor) may be integrated into the sleeve 22 to eliminate the needfor external excitation. These marker band coils may be in parallel orserial or separately excited. As another alternative, two coils may beserially arranged but with a center tap.

In some applications, it may be desirable to incorporate thermistors orthermocouples that may be monitored for an unacceptable temperature rise(e.g., 4° C.) for automatic shutdown. As a further alternative, opticalconverters may be incorporated into the sleeve so that light fibers maycommunicate a signal in and out.

Similar considerations are applicable to the piercing portion of thesleeve or obturator; however, the needs for piercing tissue may lead toother choices. As an introduction, metallic components used for MRI safemedical devices must be biocompatible and not interact with the strongmagnetic fields used during MRI imaging. Standard 300 and 400 seriesstainless steels are ubiquitous in medical device design. Thesematerials combine the features of corrosion resistance,biocompatibility, hardness and tensile properties. These materials areprimarily ferrous. The 300 series materials have less interaction withmagnetic fields than the 400 series materials, but have lower hardnessproperties, which limits their utility for sharp edges for cuttingand/or penetrating tissue. All 300 and 400 series materials havesignificant concentrations of iron, which limits their utility for MRIimaging applications.

Iron Alloys: There is at least one ferrous, austenitic alloy, whichremains non-magnetic even after severe forming operations, Super AlloyNitronic. Other related materials include Carpenter 22Cr-13Ni-5Mn, HPA50, XM-19. Alloy 316 is also relatively non-magnetic, but becomes moremagnetic as it is work hardened. The alloy compositions are as follows:TABLE 1 Steel Composition Range (%) Element Nitronic 50 316L IdealCarbon 0.06 max 0.03 max 0.06 max  Manganese 4-6 2.0 2-6 Phosphorus 0.04max 0.045 max  0.045 max  Sulfur 0.03 max 0.03 max 0.03 max  Silicon 1.0 max  1.0 max 1.0 max Chromium 20.5-23.5 16-18 16-24 Nickel11.5-13.5 10-14 10-14 Molybdenum 1.5-3   2-3 1-3 Copper Cobalt 0.1-0.30.3 max Titanium Columbium 0.1-0.3 0.3 max Aluminum Tantalum Vanadium0.1-0.3 0.3 max Tungsten Boron Nitrogen 0.2-0.4 0.4 max Iron BalanceBalance Balance

The ideal range is that range into which iron based alloys need to fallto have minimal magnetic properties.

Cobalt Alloys: Cobalt alloys are an excellent alternative. These alloysare hard and do not interact strongly with the magnetic fields. Examplesof such alloys include L-605 and MP-35. Cobalt alloys are optimized foreither wear resistance, high temperature use and/or corrosionresistance. For breast biopsy tools, the wear resistance and corrosionresistance properties are of greatest interest. The primary alloyingelement to provide these properties is the addition of chromium (U.S.Pat. No. 873,745). Molybdenum and tungsten are outstanding strengtheningagents. The addition of carbon improves the wear resistancesignificantly. The addition of up to 2.4% carbon results in theformation of carbides. An example of this alloy is the trade name,Stellite. An alternate method for improving wear is the addition of thecombination of molybdenum and silicon. An example of this alloy is thetrade name Tribaloy. This alloy has been deposited successfully as athin film.

The addition of nickel was found to improve the high temperatureperformance. An example of this alloy is Stellite 21 with approximately2.5% nickel. Later alloys such as the X-40 and L-605 have increasingnickel content to around 10%. In general alloys with the followingcomposition ranges are optimum for Co based, high tensile strength, highhardness materials: TABLE 2 Composition Range (%) Element L-605 MP-35CCM Ideal Carbon 0.05-0.15 0.025 max   0.1 max  2.4 max Manganese 1-20.15 max   1 max 0-2 Phosphorus 0.03 max 0.015 max   0.2 max Sulfur 0.03max 0.01 max 0.05 max Silicon  0.4 max 0.15 max   1 max 0-2 Chromium19-21 19-21 26-30 19-35 Nickel  9-11 33-37   1 max  0-40 Molybdenum 9-11 5-7  0-15 Copper 0-1 Cobalt Balance Balance Balance Titanium   1max 0-2 Columbium/Niobium 0-1 Aluminum 0-1 Columbium + 0-1 TantalumVanadium 0-1 Tungsten 14-16  0-20 Boron 0.01   0-0.05 Nitrogen 0.25 max0.25 max Iron   3 max   1 max 0.75 max   5 max

Nickel Based Alloys: Nickel-Chromium-Molybdenum alloys are anotherapproach to hard, non-magnetic metal alloys. Some members of this alloyclass have greater than 5% iron (Inconel 600) and nickel based alloyseven without iron can have significant magnetic properties. Thecomposition and processing of the alloy is key to its magnetic andphysical properties. Some alloys such as Inconel 625, have Rockwellhardness exceeding 95 Rb. TABLE 3 Composition Range (%) Inconel InconelElement 600 X750 M252 Ideal Carbon 0.08 0.1 0.1   2 max Manganese 0.51.0 1.0 0-2 Phosphorus  0.2 max Sulfur 0.05 max Silicon .25 0.5 0.7 0-2Chromium 15.5 15. 19 10-20 Nickel 76 72 53.5 Balance Molybdenum 10  0-15Copper 0.25 0-1 Cobalt 1.0 10 Titanium 2.5 2.5 0-2 Columbium/Niobium 0-1Aluminum 0.7 0.75 0-2 Columbium + Tantalum 0-1 Vanadium 0-1 Tungsten 0-2Boron   0-0.05 Nitrogen 0.25 max Iron 8 7 2   10 max

Composite Approaches: Soft metals, such as titanium or fully annealed316 SS have appropriate magnetic properties, but have poor hardness andthus poor cutting ability. These materials can be locally hardened atthe cutting or penetrating surface by the follow processes: (1) Brazing,welding, or joining a hard material edge to the soft metal; (2) Vapordeposition (chemical, vacuum, etc) of a hard material such a titaniumnitride; (3) Ion beam implantation; (4) Localized heat/work hardeningvia laser or frictional heating; (5) Or a combination of the abovemethods.

Non-Metallic Materials Options: Other non-metallic materials useful forcreating sharp, cutting surfaces include the following amorphous/ceramicmaterials: (1) Alumina; (2) Zirconia (including yttria stabilized); (3)Silica. Single crystal materials include: (1) Silicon; (2) Germanium;(3) Carbon in the diamond form; (4) Aluminum in the sapphire form; (5)Ruby. The single crystal cutting edges may be created using the singlecrystal properties of the materials. Preferential etches, such asalcohol-KOH on 1,0,0 silicon wafers, can be used too pattern preciseangles and thus sharp edges.

Penetrating Member Geometries: The blade geometry is important in theoptimization of the force to penetrate tissue. The early pyramidaldesign on trocars has recently been superceded by flat blade designs.The theory of point and cutting angles date back to Augur bits in1800's. Cutting theories have always been studied, developed and refinedfor wear issues, etc., in recent years. The key factor that governs thisoptimization is the geometry at the tip as torque and thrust force (theamount surgeon pushes the trocar) is fixed for a given diameter ofblade. The majority (almost 90%) of penetration forces is controlled bythe tip as it separates the layers of tissue. Using lower penetrationforces is beneficial as this causes less pain. There is 120 degreemotion of torque in both direction while inserting the blade. The thrustforce with which the blade is pushed is not measured. An assumption maybe made that the trocars are pushed at around 5 lbs. The cutting bladeis the major element of the tip, which separates (cuts) the tissue. Inthe current design (FIG. 77) there is sharp cone angle of 30 to 35degrees with a flat blade perpendicular to the surface. This inventionexplores to optimize the optimization of the tip design with offsetcutting edges with a cutting angle and a secondary flat point angle atthe center, as depicted in FIGS. 78A-78B.

Definitions: Dynamic cutting angle (α_(dyn)): The angle measured in aplane through a point on the cutting edge and perpendicular to thehorizontal line that passes that point and intercepts with the drillcenter axis, between the rake face and normal line of that plane whichcontains both the cutting edge and the cutting velocity vector. Thecutting velocity vector is the vector sum of the rotary cutting velocityvector and feed velocity vector. This is the cutting angle that may beused in separating tissue layers, with the geometry for positive anglesdepicted in FIG. 79 and for negative angles depicted in FIG. 80.

As explained above at any given point in the cutting blade there are twovelocity vectors. In the current design α=0 as the blade isperpendicular to the cutting edge. Assume the cutting edge of the bladeis divided into number of small elements (N). Each element is assumed toexperience orthogonal cutting. The method of calculating dynamic rakeangle at any instant and spatial position on the cutting edge can bedeveloped based of geometric factors. Torque at each instant can bedetermined by the following equation:$T_{\lbrack{total}\rbrack} = {\sum\limits_{i = 1}^{N}\lbrack {F_{p},{F_{n}( {{f( {\alpha_{d{(i)}},{{woc}(i)}} )} \times {r(i)}} )}} \rbrack}$Where α_(d) Dynamic Cutting Angle), and r(i) (radius of each elementfrom the axis of the drill) is varying for each element on the cuttingedge.

The difference between the current design and proposed design is thatwidth of cutting edge (WOC) change, cutting angles may be steeper (rangefrom 40 to 60 degrees) This is a converse problem of cutting as given 1in-lb torque and X lbs thrust. What is the best geometry at the tip toget lower penetration force. This can be analytically developed andtested in the wet lab.Problem statement is: T _(total)=constant−Reduce F _(n) based ofgeometry.This is possible with offset cutting edge and making more aggressivecutting angles from 40 to 60 degrees.

The cutting edge can also have multiple blades like 4 to increase theWOC. The cutting edge shall not be sharp to avoid ploughing. It may havea 5 thousand radius to optimize penetration forces. The flat blade canbe further optimized as follows as depicted in FIGS. 81A-81B.

In FIGS. 82-86, an obturator 3000 incorporates a flat blade 3002 onto ahollow shaft 3004 that provides a multi-function lumen 3006. In FIG. 83,the flat blade 3002 is attached within a vertical slot 3008 formedbetween two distal ramped triangular supports 3010, 3012. A proximal end3014 of the hollow shaft 3004 provides a pressure fitting 3016 for usingthe lumen 3006 for pneumatic or fluid transfers to an imagable sidenotch 3018 proximate to the flat blade 3002. In FIGS. 82, 84, exteriorengagement features on the proximal end 3014 include a circumferentialraised ring 3020 proximal to a circumferential ring slot 3022. In FIG.84, a vent hole 3024 through an opposite lateral side to the imagableside notch 3018 allows equalization of pressure within a sleeve or theuse of a vacuum lumen in the sleeve (not shown in FIGS. 82-86). In FIGS.85, 86, atop guide slot 3026 passes longitudinally down the proximalportion 3014 of the hollow shaft 3004 so that engagement with a sleevemay be keyed to align the imagable side notch 3018 with a side aperturein the sleeve. In FIGS. 82, 84, rounded leading and trailing edges 3028,3030 of the imagable side notch 3018 minimize tissue trauma.Alternatively, the top guide slot 3026 may allow visual indexing so thatconfirmation may be made that the imagable side notch 3018 is rotatedout of alignment with a side aperture during penetration to preventtissue entering the image side notch 3018. Thereafter, the imagable sidenotch 3018 may be rotated into alignment for imaging confirmation and/oruse of the multi-function lumen 3006.

It would be desirable to have disposable fiducial instruments thatadvantageously are fillable by the end user and may even be disposable.Thereby, clinical flexibility is enhanced by allowing the empty fiducialinstrument to have extended shelf life, simplified sterilizationprocesses, simplified storage (e.g., broader temperature range), andreduced packaging requirements. In addition, the end user may select acontrast agent or other imagable material.

In FIG. 87, a short fiducial instrument 3200 a is an example of thefudicial 262 in FIG. 4 used with a localization fixture to locate acoordinate at an external point on the patient's skin. A clearpolycarbonate body 3202 a is assembled from a valve body 3204 a attachedto a hollow snout 3206 a. An imaging lumen 3208 a passes longitudinallyfrom a proximal fill spout 3210 a proximally extending from the valvebody 3204 a, through a one-way valve chamber 3212 a into an elongatecavity 3214 a in the hollow snout 3206 a whose distal end is partiallysealed by a porous plug 3216 a. Examples of materials for the porousplug 3216 a include porous PTFE, porous polyethylene, porouspolypropylene, polystyrene, and glass frit. External threads 3218 a on aproximal end of the hollow snout 3206 a allow for engagement to aholder, such as a monocle or sleeve mount. In use, imagable fluid, suchas but not limited to those materials described herein, are insertedinto the proximal fill spout 3210 a by inserting a syringe needle (notshown) through a septum 3217 a that seals the proximal fill spout 3210a, causing a seal 3220 a to unseat in the valve chamber 3212 acompressing valve spring 3222 a as the fluid enters the elongate chamber3214 a as depicted by arrow 3224 a while air evacuates through porousplug 3216 a as depicted by arrow 3226 a. The end user continues to filluntil evidently filled as viewed through a clear polycarbonate body 3202a, when resistance is felt to forcing in more fluid, or when the fillspout 3210 a appears full, or when fluid begins to ooze through theporous plug 3216 a. It should be appreciated that a two-way valve may beincluded that would allow an over-pressure to release fluid or for auser to withdraw fluid. In addition, the septum 3217 a may suffice tohold fluid in the short fiducial instrument 3200 a.

In FIG. 88, a long fiducial instrument 3200 b is an example of animaging obturator or stylet or alternate features for a fiducial usedexternal to the patient. Although not shown in FIG. 88 for clarity, asecond open lumen may be included for inserting a tool. A piercing tipmay also be included for use as an introducer obturator with an openended sleeve. A clear polycarbonate body 3202 b has an integral valvebody portion 3204 b formed with a hollow snout portion 3206 b. Animaging lumen 3208 b passes longitudinally from a proximal pipe fitting3210 b proximally extending from the valve body portion 3204 b, througha one-way valve chamber 3212 b into an elongate cavity 3214 b in thehollow snout 3206 b whose distal end is partially sealed by a small venthole 3216 b. External threads 3218 b on a proximal end of the hollowsnout 3206 b allow for engagement to a holder, such as a sleeve hub. Inuse, imagable fluid, such as but not limited to those materialsdescribed herein, are inserted into the proximal pipe fitting 3210 b,causing a seal 3220 b to unseat in the valve chamber 3212 b compressingclosure valve spring 3222 b as the fluid enters the elongate chamber3214 b as depicted by arrow 3224 b while air evacuates through vent hole3216 b as depicted by arrow 3226 b. After filling, surface tension ofthe liquid prevents loss of fluid through the vent hole 3216 b.

While the present invention has been illustrated by description ofseveral embodiments and while the illustrative embodiments have beendescribed in considerable detail, it is not the intention of theapplicant to restrict or in any way limit the scope of the appendedclaims to such detail. Additional advantages and modifications mayreadily appear to those skilled in the art. For example, other imagingmodalities may benefit from aspects of the present invention.

1-46. (canceled)
 47. A method useful in imaging breast tissue, themethod comprising the steps of providing a sleeve having an internallumen, an open distal end, and a tissue sample notch; providing anobturator having a distal bladed portion, wherein the obturator isremovably insertable within the internal lumen of the sleeve to have thebladed portion extend from the open distal end of the sleeve and to havesample notch of the sleeve closed by the obturator; inserting theobturator into the sleeve; inserting the sleeve and obturator intotissue to be sampled, with the obturator positioned to close the samplenotch in the sleeve and with the bladed portion of the obturatorextending from the open distal end of the sleeve; and at least partiallyopening the sample notch by moving the obturator relative to the sleeve;wherein the step of at least partially opening the sample notch isperformed without withdrawing the distal bladed portion of the obturatorfrom the open distal end of the sleeve.
 48. The method of claim 47further comprising the step of imaging the sample notch to determine theposition of the sample notch with respect to a tissue mass, after atleast partially opening the sample notch.
 49. The method of claim 47comprising the step of rotating the obturator within the internal lumenof the sleeve to at least partially open the sample notch.
 50. Themethod of claim 47 comprising the step translating a portion of theobturator in a proximal direction to at least partially open the samplenotch.
 51. The method of claim 47 wherein the step of at least partiallyopening the sample notch comprises positioning a recess in the obturatorwith respect to the sample notch.
 52. A method useful in imaging breasttissue, the method comprising the steps of providing a sleeve having aninternal lumen, an open distal end, and a tissue sample notch spacedproximally from the open distal end; providing an obturator, theobturator removably insertable within the internal lumen of the sleeveto have a distal portion of the obturator extend from the open distalend of the sleeve; inserting the obturator into the sleeve; insertingthe sleeve and obturator into tissue to be sampled, with the obturatorpositioned in the sleeve to close the sample notch in the sleeve; and atleast partially opening the sample notch by rotating the obturatorrelative to the sleeve.
 53. A medical device for use in imaging breasttissue; the apparatus comprising: a sleeve having an internal lumensized to receive a biopsy device, an open distal end; and a sample notchdisposed proximally of the open distal end; an obturator having a bladeddistal end, the obturator removably insertable within the sleeve,wherein the obturator is movable within the sleeve from a firstconfiguration to a second configuration; wherein in the firstconfiguration the bladed distal end extends from the open distal end ofthe sleeve and the obturator substantially closes the sample notch inthe sleeve; and wherein in the second configuration the bladed distalend extends from the open distal end of the sleeve and a portion of theobturator is positioned to substantially open the sample notch in thesleeve.
 54. The device of claim 53 wherein the obturator comprises arecess, and wherein the recess in the obturator is spacedcircumferentially from the sample notch in the first configuration, andwherein the recess in the obturator is generally aligned with the samplenotch in the second configuration.
 55. The device of claim 53 whereinthe obturator is rotatable within sleeve from the first configuration tothe second configuration.
 56. The device of claim 53 wherein a portionof the obturator adjacent the sample notch in the first configuration isdisplaced proximally of the sample notch in the second configuration.